Hello everybody.
I'm about to start building a BA3 front stage to feed my Hyopex Ncore400 system and have some questions:
Regarding to FETS, which option between the following at my hand is better?:
1.- 2SK170/2SJ74 "V" grade NOT MATCHED + 2SJ313/2SK2013 NOT MACHED
2.- 2SK170/2SJ74 "V" grade MATCHED + FQP3P20/FQP3N30 to be mached (I can find cheap and would match)
3.- 2SK170/2SJ74 "V" grade MATCHED + 2SJ162/2SK1058 NOT MATCHED but same batch
And regarding to the regulated PS: I arrived late to SALAS SSLV and there's no stock for Glassware PS-19, so y chances are:
4.- High current low noise LT1083CP dual rail power supply assembled board ! | eBay
5.- HYPEX SMPS400/180 with +/-42VDC output stepped down to +/-24V. In this case, Which circuit would do with good quality?
Thank you.
I'm about to start building a BA3 front stage to feed my Hyopex Ncore400 system and have some questions:
Regarding to FETS, which option between the following at my hand is better?:
1.- 2SK170/2SJ74 "V" grade NOT MATCHED + 2SJ313/2SK2013 NOT MACHED
2.- 2SK170/2SJ74 "V" grade MATCHED + FQP3P20/FQP3N30 to be mached (I can find cheap and would match)
3.- 2SK170/2SJ74 "V" grade MATCHED + 2SJ162/2SK1058 NOT MATCHED but same batch
And regarding to the regulated PS: I arrived late to SALAS SSLV and there's no stock for Glassware PS-19, so y chances are:
4.- High current low noise LT1083CP dual rail power supply assembled board ! | eBay
5.- HYPEX SMPS400/180 with +/-42VDC output stepped down to +/-24V. In this case, Which circuit would do with good quality?
Thank you.
V grade are between 10-20ma Idss, the low end of that range is useable, but as they get higher, the dissipation becomes a problem.
The Hypex would work fine, as would the LT1083 board you linked. I'd personally choose the linear supply.
The Hypex would work fine, as would the LT1083 board you linked. I'd personally choose the linear supply.
Still not bought any fet, but seller says that V grade 2sk170/2sj74 are 0,1ma idss.
Any of the other options are matched.
Regarding to the PS, I will go for the LT1083 with a toroid 18-0-18V 30VA.
Will be enough??
Thanks a lot.
Any of the other options are matched.
Regarding to the PS, I will go for the LT1083 with a toroid 18-0-18V 30VA.
Will be enough??
Thanks a lot.
The Glassware Item# LV-Regulator is in stock at the moment, and it is even quieter than the PS-19. You would need two of them, each set at 24V. You would connect the ground to the - output of one PS and also to the + output of the other PS to get + and - 24VDC rails. Do not use a center tap transformer but instead use a dual secondary transformer. I did this and it works great, but it does cost more and take up more space, but I tend to overkill.
Hi Guys.. this thread is a really good read... Ive been toying with the idea of my next Line Amp stage and been looking at a range of ideas from Borbely Super-Buffer to the PASS BOZ and now the PASS BA-3 Gain Stage.
I dont have time to design and build my own PCB so Im really looking for a group build much like the BA-3 offers.
My main concern is how well will the BA-3 gain stage drives real-world longer cables and PAmp. Has anyone put a scope on the BA-3 driving +5m cables plus amp with say 20k Zin and looked at how well or badly damped its ringing is to a 10kHz sqwave??
I was also thinking of putting a B1 Buffer at the front end to provide isolation from level dividers for ea input and the vol control pot. Im assuming that 20k to 50k pot is optimal for the BA-3?
So far the BA-3 (+B1) is almost a done deal for me..
I dont have time to design and build my own PCB so Im really looking for a group build much like the BA-3 offers.
My main concern is how well will the BA-3 gain stage drives real-world longer cables and PAmp. Has anyone put a scope on the BA-3 driving +5m cables plus amp with say 20k Zin and looked at how well or badly damped its ringing is to a 10kHz sqwave??
I was also thinking of putting a B1 Buffer at the front end to provide isolation from level dividers for ea input and the vol control pot. Im assuming that 20k to 50k pot is optimal for the BA-3?
So far the BA-3 (+B1) is almost a done deal for me..
Is there a way to to use the BA3 as the front end for bridged F4-Mono-blocks ? I have still some around.
Ideally in a way that somone could really have full balnced operation from the DAC to the F4-Outputstage...but with the optin of SE-input, so like a diff-amp...
....basically using two stereo-Pcb ? Or is the BA3 the wrong platform for this ?
Ideally in a way that somone could really have full balnced operation from the DAC to the F4-Outputstage...but with the optin of SE-input, so like a diff-amp...
....basically using two stereo-Pcb ? Or is the BA3 the wrong platform for this ?
This may be of interest:
http://www.diyaudio.com/forums/pass-labs/201281-burning-amp-ba-3b-balanced.html
http://www.diyaudio.com/forums/pass-labs/201281-burning-amp-ba-3b-balanced.html
Yes, of course. You'll need 2 of the BA-3 front end boards, but they were always intended to be wired balanced if you so choose. It's the perfect driver for Balance F4
http://www.diyaudio.com/forums/pass-labs/201281-burning-amp-ba-3b-balanced.html
http://www.diyaudio.com/forums/pass-labs/201281-burning-amp-ba-3b-balanced.html
Already ordered, thx a lot...may I ask two additional questions:
- PSU ? I would like to build it into the F4enclosure, so I could add itto the F4-Psu ? oK or should it have a sep PSU ? Regulated ?
- Which Voltage in the PSU to drive bridged F4 ideally ?
THX a lot !
- PSU ? I would like to build it into the F4enclosure, so I could add itto the F4-Psu ? oK or should it have a sep PSU ? Regulated ?
- Which Voltage in the PSU to drive bridged F4 ideally ?
THX a lot !
I would recommend a separated psu with separate transformer too. Check the store's super regulator and salas' SSLV shunt regulator.
What case are you using for each f4?
It might be a tight fit if you are using the store's 4u case. And what will you use volume control and source selection? It might be easier to build the preamp into its own chassis with psu and volume/source selection.
Has anyone used the b3a as an I/V-stage ? I am running a Buffalo 3 in dual mono, so it gives me 32ma output...would be very nice, if the b3a can produce enough gain to drive a F4 directly...
BA-3 can produce as much gain as F4 needs. It was made to drive an un-buffered F4 output stage. It has lots and lots of power, and sounds beautiful.
Hello.
First of all, thanks to 6L6 for the preamp build guide.
I'm testing my BA3 front stage and I allways have 0 volts ACCROSS R12 as said in this guide, but I have some milivolts (20mV) if I take measures between the 2 legs of C3.
It happens in my board that any change at P1 or P2 pots makes no DC offset accross R12. I do have 0 volts always.
Is this ok?
Thanks in advance
First of all, thanks to 6L6 for the preamp build guide.
I'm testing my BA3 front stage and I allways have 0 volts ACCROSS R12 as said in this guide, but I have some milivolts (20mV) if I take measures between the 2 legs of C3.
It happens in my board that any change at P1 or P2 pots makes no DC offset accross R12. I do have 0 volts always.
Is this ok?
Thanks in advance
Not across R12...between R12 and ground.
You need to measure between R12 and C3 and ground to get DC offset. Make sure you are not measuring after C3 (the 10uf cap nulls DC). An easy place to measure is the lead of C3 that faces the center of the board. Positive meter lead on that lead of C3, Negative meter lead to ground.
You need to measure between R12 and C3 and ground to get DC offset. Make sure you are not measuring after C3 (the 10uf cap nulls DC). An easy place to measure is the lead of C3 that faces the center of the board. Positive meter lead on that lead of C3, Negative meter lead to ground.
